The present invention relates generally to the field of woodworking, and, more particularly, to a system and method for forming dovetail joints.
Dovetails are used in carpentry and cabinetry to join two wooden boards together at 90 degree angles. One board, called the tail board, has sockets cut in a trapezoidal (i.e., dovetail) shape, with xe2x80x9ctailsxe2x80x9d being formed in between the sockets. The other board, called the pin board, has pins cut to fit in the sockets. When the two boards are joined together, the result is a durable, eye-pleasing joint.
Dovetails have traditionally been cut by hand with a saw and a chisel xe2x80x94a process involving much time and skill. A number of devices have been created to simplify the process of cutting dovetails. A typical dovetail-cutting device uses a set of templates (or xe2x80x9cjigsxe2x80x9d) and a specially designed set of router bits. By positioning the templates over the pin board and tail board and guiding a router fitted with the special router bit through the templates, it is possible to cut dovetails. This method, however, has drawbacks, such as a large amount of router noise and dust, and the possibility that the wood will be torn during the routing process. Additionally, due to the limited sizes and configurations of the templates and router bits, these devices can generally be used only to cut dovetails for boards up to 24 inches long with pins spaced no more than xc2xe-inches apart, and can usually be used to form only xe2x80x9chalf-blindxe2x80x9d or xe2x80x9clapxe2x80x9d style dovetails (dovetails in which the pin board is not cut all the way through its thickness). Still further, assembling, aligning and attaching the templates over the pin and tail boards can be a time-consuming process. Finally, the templates can only be used to cut uniformly spaced and sized pins and tails, which do not display the individual and unique variations in shape and size that are characteristic of fine woodworking.
In view of the foregoing, there is a need for a system for forming dovetail joints that overcomes the limitations and drawbacks of the prior art.
A system according to the present invention may be used to cut dovetail joints with sockets having arbitrary and non-uniform sizes and pitches. The system may also be used to cut dovetails in wooden boards having arbitrary lengths and thicknesses.
In accordance with the invention, a trapezoidal hollow mortising chisel is provided, which is mounted on a drill press for cutting the tail board of a dovetail joint. The trapezoidal mortising chisel has a guide tube with a trapezoidal cross-section, and a drill bit mounted in the center of a guide tube. When attached to a drill press, the trapezoidal mortising chisel may be used to make a trapezoidal cut through a wooden board. Each socket in the tail board has two slanted sides, which correspond to the non-parallel sides of the trapezoid that defines the shape of the guide tube. Thus, the trapezoidal mortising chisel may be used to cut tail board sockets, with sides having angles corresponding to the pitch of the non-parallel sides of the trapezoid.
Once the tail board has been cut, a standard square hollow mortising chisel can be mounted on a drill press for cutting the sockets in the pin board. The work table of the drill press is tilted so that, during the cutting processes, a slope can be placed on the socket, thereby allowing a tail from the tail board to fit into it. The slope corresponds to the pitch of the trapezoidal mortising chisel that was used to cut the tail board. The system includes means for aligning the tilt of the work table at an angle that corresponds to the desired pitch. Exemplary means include a circular washer, mountable about the tilt axis of the work table, where the washer has a pair of holes located on either side of a reference radius and at a given angle from the reference radius, where the reference radius corresponds to the horizontal (non-tilted) position of the work table. The holes receive the alignment pin of a drill press, thereby allowing the work table to be aligned at the given angle of tilt.
Other features of the invention are described below.